The sea-to-air flux of dimethylsulphide（DMS） is one of the major sources of marine biogenic aerosol, and can have an important radiative impact on climate, especially in the Arctic Ocean. Satellite-derived aerosol o...The sea-to-air flux of dimethylsulphide（DMS） is one of the major sources of marine biogenic aerosol, and can have an important radiative impact on climate, especially in the Arctic Ocean. Satellite-derived aerosol optical depth（AOD） is used as a proxy for aerosol burden which is dominated by biogenic aerosol during summer and autumn. The spring sea ice melt period is a strong source of aerosol precursors in the Arctic. However, high aerosol levels in early spring are likely related to advection of continental pollution from the south（Arctic haze）.Higher AOD was generally registered in the southern part of the study region. Sea ice concentration（SIC） and AOD were positively correlated, while cloud cover（CLD） and AOD were negative correlation. The seasonal peaks of SIC and CLD were both one month ahead of the peak in AOD. There is a strong positive correlation between AOD and SIC. Melting ice is positively correlated with chlorophyll a（CHL） almost through March to September,but negatively correlated with AOD in spring and early summer. Elevated spring and early summer AOD most likely were influenced by combination of melting ice and higher spring wind in the region. The peak of DMS flux occurred in spring due to the elevated spring wind and more melting ice. DMS concentration and AOD were positively correlated with melting ice from March to May. Elevated AOD in early autumn was likely related to the emission of biogenic aerosols associated with phytoplankton synthesis of DMS. The DMS flux would increase more than triple by 2100 in the Greenland Sea. The significant increase of biogenic aerosols could offset the warming in the Greenland Sea.展开更多
Global warming has been reported to enhance thermal stratification and decrease the mixlayer depth(MLD)in waters due to higher surface water temperatures,especially in summer.Previous studies were conducted for indivi...Global warming has been reported to enhance thermal stratification and decrease the mixlayer depth(MLD)in waters due to higher surface water temperatures,especially in summer.Previous studies were conducted for individual cases or specific periods.At present,there is a lack of global assessments on the influence of climate warming in different seasons on thermal stratification.The ECMWF Reanalysis v5(ERA5)dataset was used to estimate the variability of water body mixing and its drivers in different seasons and regions.Results indicate that global warming could enhance thermal stratification and decrease the MLD globally in summer.Wind speed was the primary driver of MLD changes,followed by temperature.However,ice melt due to global warming enhanced the mixing in icecovered waters in the Northern Hemisphere,and early ice melt led to early mixing.Ice depth was the primary driver of MLD changes in the Northern Hemisphere due to delayed ice formation and earlier melting,while wind speed was the primary driver in other regions or during ice-free seasons.The enhanced mixing due to earlier ice melt out in late winter and early spring could promote water circulation and nutrient turnover,and replenish dissolved oxygen in deep water,thereby promoting the maximum biomass of cyanobacteria and advance harmful algal blooms.展开更多
基金The National Natural Science Foundation of China under contract No.41276097
文摘The sea-to-air flux of dimethylsulphide（DMS） is one of the major sources of marine biogenic aerosol, and can have an important radiative impact on climate, especially in the Arctic Ocean. Satellite-derived aerosol optical depth（AOD） is used as a proxy for aerosol burden which is dominated by biogenic aerosol during summer and autumn. The spring sea ice melt period is a strong source of aerosol precursors in the Arctic. However, high aerosol levels in early spring are likely related to advection of continental pollution from the south（Arctic haze）.Higher AOD was generally registered in the southern part of the study region. Sea ice concentration（SIC） and AOD were positively correlated, while cloud cover（CLD） and AOD were negative correlation. The seasonal peaks of SIC and CLD were both one month ahead of the peak in AOD. There is a strong positive correlation between AOD and SIC. Melting ice is positively correlated with chlorophyll a（CHL） almost through March to September,but negatively correlated with AOD in spring and early summer. Elevated spring and early summer AOD most likely were influenced by combination of melting ice and higher spring wind in the region. The peak of DMS flux occurred in spring due to the elevated spring wind and more melting ice. DMS concentration and AOD were positively correlated with melting ice from March to May. Elevated AOD in early autumn was likely related to the emission of biogenic aerosols associated with phytoplankton synthesis of DMS. The DMS flux would increase more than triple by 2100 in the Greenland Sea. The significant increase of biogenic aerosols could offset the warming in the Greenland Sea.
基金Supported by the 14th Five-Year National Key Research and Development Program of China(No.2022YFC3202004)the National Natural Science Foundation of China(No.42220104010)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20220041)the Young Scientists Group Project of Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,China(No.E1SL002)。
文摘Global warming has been reported to enhance thermal stratification and decrease the mixlayer depth(MLD)in waters due to higher surface water temperatures,especially in summer.Previous studies were conducted for individual cases or specific periods.At present,there is a lack of global assessments on the influence of climate warming in different seasons on thermal stratification.The ECMWF Reanalysis v5(ERA5)dataset was used to estimate the variability of water body mixing and its drivers in different seasons and regions.Results indicate that global warming could enhance thermal stratification and decrease the MLD globally in summer.Wind speed was the primary driver of MLD changes,followed by temperature.However,ice melt due to global warming enhanced the mixing in icecovered waters in the Northern Hemisphere,and early ice melt led to early mixing.Ice depth was the primary driver of MLD changes in the Northern Hemisphere due to delayed ice formation and earlier melting,while wind speed was the primary driver in other regions or during ice-free seasons.The enhanced mixing due to earlier ice melt out in late winter and early spring could promote water circulation and nutrient turnover,and replenish dissolved oxygen in deep water,thereby promoting the maximum biomass of cyanobacteria and advance harmful algal blooms.
